Field of the Disclosure
Embodiments of the present disclosure generally relate to a printed circuit board (PCB) having a shielded patterned ground structure (PGS).
Description of the Related Art
The latest generation of hard disk drives (HDDs) utilize PCBs outside of the HDDs with silicon on chip (SoC) technology. Traces are used to run the electrical current from the SoC to the edge of the PCB. A common mode current flows through the traces typically and thus generates electromagnetic interference (EMI). The magnitude of the EMI can cause problems for hard disk drive operation at certain frequencies.
To solve the EMI problem, a surface mounted common-mode filter can be used. However, a surface mounted common-mode filter, while correcting EMI, impacts signal integrity and thus is not a viable solution. Another possible solution is to simply change the connection to the PCB, but such a change impacts space requirements and signal integrity. What is needed is a way to deal with the common mode current problem without impacting the signal integrity.
Therefore, there is a need in the art to reduce and/or eliminate common mode current in PCBs which leads to undesirable EMI.